Automatic telephone system



June 28, 1932. M. MATHIAS AUTOMATIC TELEPHONE SYSTEM Filed Nov. 17, 1930 2 Sheets-Sheet 1 H M m n E U rm 80/1 00 UQOJGO J00 find f0 QI/n. 8 fob 00 33/3 .5 f 05 OFQIB f f U u m v V M M w w 7 5 v v v v m w Maximilian Ma Patented June 28, 1932 UNITED STATES PATENT oFFics MAXIMILIAN MATI-IIAS, OF BERLIN, GERMANY, ASSIGNOR TO SIEMENS t HALSKE AKTIENGESELLSGHAFT, OF SIEMENSSTADT, NEAR BERLIN, GERMANY AUTOMATIC TELEPHONE SYSTEM Application filed. November 17, 1930, Serial No. 496,303, and. in Germany December 12, 1929.

The invention relates to a circuit arrangement for telephone systems with automatic operation.

In such systems experience has shown that for each group of subscribers lines a definite number of connectors is necessary dependent upon the number of simultaneous connections set up during the busy hour. During the greater part of the day, however, some of these connectors are very little used since the busy hour occurs only at' particular times of the day. The greatest density of traffic, however, occurs at difierent groups at difi en ent times.

The object of the present invention is to reduce the number of connectors which are necessary for dealing with the peak load but which are not used in ordinary operation and are, therefore, uneconomically employed. This is efliected in that a portion of the connectors of the group are accessible in known manner over individual trunk lines from the switches of the preceding switching stage, while each of the remaining connectors of the group is connected with a connector of another group to a common trunk line which is connected with various outlets from the preceding switching stage. This permits each connector which is not used during a portion of the day to be arranged in such a manner that certain of the control devices are provided in common, therefore, an appreciable saving in switching devices is effected without any reduction in the number of connectors which are necessary for dealing with the peak load in each group.

The two figures show one embodiment of the invention, and Fig. 1 indicates the connection of the trunk lines VL between group selectors GW and connectors LIV; I, II, and III indicate three hundred groups of con nectors. For each of these groups only four connectors are shown. The first two connectors of each group are connected in known manner with the trunk lines VLl, VL2, VL3, VLt, VL'Z', VLS from the appropriate level of the preceding group selectors. The last but one connectors of the three hundred groups are connected together and extend over the common trunk line VL5 to the last but one contact of each level of the group selectors while the last connector of the individual hundred groups are connected in common over the trunk line VL6 with the last contact of each level or the individual. group selectors.

Fig. 2 shows the circuit arrangement of three such common connectors 71, W2, IVS, which are accessible over the common trunk line VLa, VLZJ, by way of the three means of access Z1, Z2, Z3 from the preceding group selectors.

The arrangement operates in the following manner: Suppose e. g. that switch W2 is seized by way of access Z2 from the preceding group selector, relay C2 operates from earth, battery, contact 10, oil-normal contact 2102, winding I of relay C2, c-lead, earth, preceding group selector which is not shown. Relay C2 operates its contact 302 to the position 1-02, thereby completing a locking circuit for itself. Moreover, it operates contact 502 to position 602 and contact '7 02 to position 802 and closes contact 902. Relay B thereupon operates from earth, contact 902, relay B, battery, earth. Relay B thereupon opens contact 16 and closes contact 10?). The opening of contact 1?) prevents relays Cl and C3 being energized as long as switch I2 is in use, and thus prevents switches IVl and 3 bein seized at the same time.

It now interrupted earth is connected to the a-lead in the group selector in order to operate the connector N2, relay A is operated a corresponding number of times. On each energization it operates contact 390 to position 11a and thereby closes a circuit for the vertical magnet H2 from earth, contacts 110, winding I of relay V, 12%, 1303, 802, 14102, vertical magnet H2, battery, earth, so that the wipers of the switch 2 are raised in this manner to the desired level. On the first vertical step the off-normal contacts 15702 are closed so that relay M2 operates from earth, contact 15702, relay M2, battery, earth, and closes contact 16722.2 and operates contact 179222 to the position 187212. Simultaneously with the first energization of the vertical magnet H2 relay V is energized in the same circuit over its winding I and holds up throughout the train of impulses owing to the intermittent short-circuiting of its winding II. Accordingly, contact 19?) is held open throughout the series of impulses so that no circuit is completed for relay U over its winding I and it cannot complete the circuit of the rotary magnet D2 by operating contact 12a to the position 21a.

At the end of the train of impulses relay V deenergizes and brings up relay U from earth, contacts 16 2712, 19v, 2003, 602, winding I of relay U, contacts 1803, 802, 14102, vertical magnet H2, battery, earth. Relay U operates its contact 12a to position 21%, opens its contact 83% and closes its contact 23a.

hen the next series of impulses arrives over the a-lead, relay A again operates correspondingly, and each time closes a circuit for the magnet D2 from earth, contact 11a,

winding I of relay V, 21a, 2229, 181712, rotary magnet D2, battery, earth. During this series of impulses relay V again energizes so that relay U is held energized over its second winding in the circuit, earth, contacts 10?), 23a, 28?), winding II of relay U, battery, earth, and thereupon maintains contact 29% in the position 30%.

After switch 2 has been set in this manner by the last train of impulses on to the desired subscribers line, if this line is idle relay P operates from earth, contacts 106, 23a, 2&1), windings II and I of relay P, c-wiper of the switch V2, to battery in the preselector (not shown) of the wanted subscribers line. Upon the operation of relay P, contacts 2529, 26 and 27p are closed so that the seized subscribers line is guarded against further seizure by the short-circuiting of winding II of relay P and the line VLa, BLb is switched through to the subscribers line. Relay P, moreover, on operating operates contact 22 to the position 23 so that in consequence of the slow release of relay U, relay V is energized over its third winding in the circuit, earth, slow interrupter LU, contact 3010, winding III of relay V, contacts 313/, 23 181772, magnet D2, battery, earth. Relay V closes its contact 320), and thereby connects ringing current from the ringing lines RM to the outgoing a-lead. On the release of relay U contact 30% is returned to position 29% so that thereafter relay V is only energized every five seconds and, therefore, transmits ringing current to the wanted subscriber for these intervals.

When the subscriber replies, relay Y operates from earth, relay Y, contact 2729, b-wiper of the switch W2, subscribers loop, a-wiper of the switch V2, contact 26 relay A, battery, earth. Relay Y opens its contact 31y and thereby stops the transmission of ringing current.

If the wanted party is busy, relay P does not operate and the calling party receives busy tone in the usual manner, which is not shown.

Instead of setting up a connection in this manner by the setting of only a particular connector, the connection may be set up in such a manner that all the connectors associated with the common trunk line are operated on to the same line by the incoming series of impulses, while the connection to the desired line is effected by switching means associated with each connector which become operative on the seizure of a particular access to the trunk line. On the termination of the conversation the release of the connection is effected by the calling party, and by opening the c-lead in the preceding group selector relay C2 is deenergized so that relay B deenergizes also and relay P is deenergized in turn by the opening of its circuit at contact 10?). The operation of contact 2329 to the position 22;) thereby produced closes a circuit for the rotary magnet D2 from earth, battery, magnet D2, contacts 187212, 227), 38a, 3401, 502, 2003, 191;, 161122, earth.

Magnet D2 thereupon advances the wipers of the switch one step and at the same time short-circuits itself at its interrupter contacts 35(Z2. Magnet D2 thereupon releases so that its energizing circuit again becomes operative,

and by this second energization the wipers of the switch are advanced a further step. Contact 35(Z2 is then again closed so that the mag not again releases and the cycle continues until the switch 2 reaches its normal position. When this occurs contact 2702 is again closed and 157a2 opens so that the circuit for relay M2 is interrupted and contact 167712 is opened and 18m2 is returned to position 17 m2. All the apparatus is then restored to normal.

What is claimed is:

1. In an automatic telephone system, a selector having a plurality of groups of bank contacts, a plurality of groups of connectors, individual trunk lines extending from the first group of selector bank contacts and terminating in connectors in'the first group of connectors, other individual trunk lines extending from another group of said selector bank contacts and terminating in another group of connectors, and other trunk lines multiplied to both groups of said selector bank contacts and common to a connector in each of said connector groups.

2. In an automatic telephone system, a

plurality of groups of connectors, individual trunk lines over which certain of the connectors in each of the groups are accessible to the preceding switches, and a common trunk line over which the remaining connector in each group is accessible to said preceding ii;

switches.

3. In an automatic telephone system, a plurality of groups of connectors, individual trunk lines over which certain of the connectors in each of the groups are accessible to the preceding switches, a common trunk line over which the remaining connector in each group is accessible to the preceding switches, and switching means common to all the connectors connected to the common trunk line for effecting the necessary operations for completing a connection.

4. In an automatic telephone system, a plurality of groups of connectors, individual trunk lines over which certain of the connectors in each of the groups are accessible to the preceding switches, a common trunk line over which the remaining connector in each group is accessible to said preceding switches, a test conductor individual to each connector connected to the common trunk line, and means associated with said test conductor for preparing for operation the connector individual to said test conductor.

5. In an automatic telephone system, a plurality of groups of connectors, individual trunk lines over which certain of the connectors in each of the groups are accessible to the preceding switches, a common trunk line over which the remaining connector in each group is accessible to the preceding switches, means associated with the common trunk line for receiving incoming impulses, a test relay associated with each connector connected to the common trunk line, means effective upon the operation of a test relay for preparing for operation the set ting circuit of the associated connector, and means operative under control of the impulse receiving means for positioning said connector.

6. In a telephone system, a plurality of groups of lines, a like plurality of groups of connectors, individual trunk lines over which certain of the connectors in each of the groups are accessible to the preceding switches to establish connections to subscribers in any of said groups of lines, and a common trunk line over which the remaining connector in each of said groups is accessible to said preceding switches to establish connections to subscribers in any of said groups of lines.

7. In a telephone system, a connector comprising only operating magnets and a set of wipers for completing connections to subscribers in one hundred group of lines, a like connector for completing connections to subscribers in a different hundred group of lines, a common trunk line over which said connectors are accessible to preceding switches, a test conductor individual to each of said connectors for preparing for operation the connector individual thereto, a controlling relay apparatus adapted to be temporarily associated with either of said connectors, and means including said controlling relays operated responsive to the seizure of one of said connectors for disabling the test con- MAXIMILIAN MATHIAS. 

